Worldwide, the three of the most significant trends in the telecommunications industry are the rapid growth in the number of mobile subscribers, the adoption of Voice over Internet Protocol (VoIP) as the underlying transport method for voice services, and the steadily increasing number of broadband Internet connections for both residential and business users. According to GSM World, as of early 2007 there are 2.2 billion mobile telephony subscribers worldwide, and approximately 82% are on the Global System for Mobile (GSM) Communications standard and recent updates such as UMTS. The International Telecommunications Union (ITU) expects that approximately 50% of all international phone calls will have some VoIP component in 2007. According to IMS Research, the number of fixed broadband connections worldwide will grow from 150 million to 400 million between 2005 through 2009. In addition, there are approximately 700 mobile operators worldwide.
Fixed-mobile convergence is a new service at the intersection of all three above trends for mobile operators. If mobile subscribers have a broadband Internet connection, service providers would like to leverage that connection to offer a seamlessly integrated voice service, while the subscriber accesses traditional mobile telephony outside their residence or office. By using a broadband Internet connection and VoIP, potentially higher quality and lower cost voice services can be delivered by the mobile operator, while also offloading traffic from the mobile network. In addition to lower costs and higher quality, subscribers can access a seamless voice service, whereby one telephone number and handset can be used for both mobile and “land-line” services. Finally, fixed-mobile convergence allows mobile operators to effectively compete against both traditional land-line telephone companies and new, competitive VoIP services.
Two primary methods exist for mobile operators to provide a fixed-mobile convergence service in a residential environment with existing handsets, where the legacy analog phone line is not required. The first method requires subscribers to obtain a dual-mode handset and access the network through unlicensed mobile access (UMA), traditionally through the 802.11a/b/g/n connection, also known as wireless fidelity (Wi-Fi). A benefit of UMA is that the unlicensed frequencies around 2.4 GHz can be utilized freely by the operators and subscribers, within regulatory limits for reasonable transmitted power levels. Example vendors offering mobile operators UMA solutions include Kineto, Alcatel, Nokia, and Ericsson, among others. For home use, the subscriber should have Wi-Fi service set up and configured in their residence or from a nearby access point.
An alternative approach for offering fixed-mobile convergence is to deploy a “user base station” or femtocell, directly within the subscribers' premises, such at a home or office. Another common term in the industry for femtocell is “home base station”. With a femtocell, the handset accesses the femtocell base station through traditional licensed spectrum, and the handset connects to the femtocell via a radio link that implements traditional mobile network standards. The power levels between the femtocell and the attached mobile station (MS) are generally much lower than the power levels between a macrocellular base transceiver station (BTS) and MS, since the limited range of the femtocell is intended to cover the subscriber's premises. In most femtocell designs, connectivity to the mobile network or public switched telephone network (PSTN) is provided through an Internet connection, and calls are connected through Voice over Internet Protocol (VoIP) technologies. Other techniques are possible, such as utilizing a Bluetooth connection between the mobile handset and a personal computer or peripheral, as implemented in the Glide product from British Telecom (BT). In general, mobile operators are currently focusing on the UMA and femtocell approaches.
Although UMA can be expected to acquire some market share for fixed-mobile convergence, femtocell based solutions have significant benefits. For example, ABI Research forecasts that by 2011 there will be 102 million subscribers on femtocell products at 32 million access points worldwide, indicating substantial benefits of femtocells for both subscribers and mobile operators due to numerous reasons. First, the number of handsets capable of supporting a Wi-Fi connection are far fewer than the number of handset deployed worldwide which support existing digital mobile telephony standards such as Global System for Mobile Communications (GSM), Code Division Multiple Access (CDMA), Universal Mobile Telecommunications System (UMTS), and CDMA2000. Second, handsets that support Wi-Fi generally have higher manufacturing costs than handsets without the Wi-Fi functionality. Mobile operators would prefer to offer a fixed-mobile convergence solution without requiring widespread upgrade of existing handsets or cellular network infrastructure, in order to reduce costs for both subscribers and the operator. Third, the power levels required to transmit voice over Wi-Fi are widely recognized as higher than using a femtocell, resulting in superior battery life for the femtocell approach to fixed-mobile convergence. Similarly, the radio link for most mobile telephony services is optimized for long-range, digitized voice transmission, while Wi-Fi is optimized for localized broadband data connectivity. Consequently, applying mobile telephony standards on the femtocell generally provides a more robust radio link between the MS and the femtocell in a subscriber's premises than a Wi-Fi connection.
Simply reducing the size of a traditional base transceiver station (BTS) or even a picocell to a form factor acceptable for installation at a subscriber's premises could provide a technically functional femtocell. However, without significantly altering the hardware architecture and adding advanced VoIP capabilities, a simply “smaller” BTS or picocell priced at several thousand dollars would clearly have limited adoption with subscribers. There are many other desirable features for subscribers and mobile operators that a simply “smaller” BTS would normally be unable to provide.
There is a need in the art for femtocells that can deliver a high quality and low cost fixed-mobile convergence solution. What are needed in the art are femtocells that minimize component costs and the costs of servers operated by the Service Provider. There is a need for femtocells that can intelligently limit interference of radio transmissions with the surrounding macrocellular network, especially on a licensed spectrum not owned by the mobile operator. Similarly, there is a need in the art for a femtocell system that can transmit at low power levels for both the femtocell and the mobile station (MS), which can be carefully managed to provide high quality calls on the subscriber's premises and the immediate vicinity, such as a typical range up to 50 meters from the femtocell.
Another need exists in the art for femtocells that can intelligently determine higher power levels with corresponding longer range service are acceptable, based on algorithms that verify interference with nearby BTS at the higher transmit power levels would be minimal. There is a need in the art for femtocells that can support flexible configuration parameters for both VoIP and base station functionality, such as server names, identifying tokens for the femtocell, allowed licensed frequencies for radio transmission, power levels, among many others. A further need exists in the art for a femtocell system that supports configuration parameters that can be easily updated by a service provider upon provisioning of a femtocell, or if the subscriber or mobile operator request changes in the service for a femtocell.
Therefore, a need exists in the art for femtocells that can support VoIP trunking techniques to combine the audio packets from several simultaneous calls through each femtocell into larger VoIP packets, thereby reducing bandwidth utilization on the subscriber's Internet connection. This combining of media packets can reduce the routing processing load on the subscriber's terminal equipment for the Internet connection. Another need exists in the art for femtocells that can leverage the personal computer to further reduce component costs of the femtocell system.
The processing capability of the central processing unit (CPU) on most personal computers is relatively idle. Thus, there is a need in the art for femtocells that can employ VoIP client and software defined radios (SDR) on the personal computer in order to harness the underutilized processing power so that several simultaneous calls, or channels, can be supported by each femtocell. Another need exists in the art for “stand alone” femtocell that connects mobile calls without a personal computer and that can achieve the benefits of service through femtocells when compared to UMA over Wi-Fi.
Another need exists in the art for femtocells that can support both voice and data services, such as Short Message Service (SMS) or Multimedia Messaging Service (MMS). A further need exists in the art for femtocells that can support the encryption of communications in both the radio spectrum and through the Internet and which may be optionally configured, depending upon the security requirements of the subscriber, mobile operator, service provider, or appropriate regulatory agencies.
What is also needed are femtocells that can synchronize their timing with the surrounding macrocellular network, if present, in order to facilitate handoff of a MS from a femtocell to a mobile network. There is a need for femtocells that are sufficiently synchronized with a surrounding mobile network, in order to significantly reduce the probability that an active call initiated on the femtocell will drop upon handover attempts to a surrounding BTS as the MS moves out of the femtocell range. Moreover, a need exists in the art for femtocells which can leverage advanced VoIP techniques and network monitoring in order to deliver the highest possible call quality.
Another need exists in the art for femtocells that support VoIP techniques that may include forward error correction to compensate for meaningful packet loss between the subscriber's Internet connection and the Service Provider's network, native transmission of the MS codec to the terminating endpoint to avoid transcoding, disabling checksums on the UDP packets containing media, and trunking of media for multiple simultaneous calls. There is a need for service to femtocells which can support routers and modems at the subscribers' premises that implement network address translation (NAT), which can result in a private address that is not routable on the public Internet.
A need exists for femtocells that can a intelligently detect Internet routing quality issues, and which can attempt to compensate for them, and ultimately temporarily disable base station service, if significantly higher quality service will be provided by a surrounding macrocellular BTS. If the quality of the Internet connection for a femtocell system degrades to a sufficient level, there is a need for the femtocell to automatically allow subscribers to use the macrocellular network for superior voice quality.
There is a need for femtocells to support such cutover to mobile networks when the MS is within the femtocell service area and to provide for automatically management of this feature. In addition, there is a need for a femtocell system that allows a service provider to route calls between endpoints entirely through the Internet and completely bypass the traditional PSTN or mobile networks, if the other party is also located on the Internet, such as at a VoIP phone or softphone on a PC, for instance. There is a need for such routing that would bypass the termination costs traditionally associated with sending a call through the PSTN or mobile networks.
Furthermore, a need exists for femtocells that are readily transportable by the end user and preferably small enough to attach to a subscriber's keychain, similar to a USB “memory stick” and that may be of a size similar to a USB Ethernet Port adapter. A further need exists in the art for a portable femtocell that can also be quickly and easily installed, for example as simple as plugging a device into the USB port of a personal computer or laptop. There is a need in the art for a system that supports such combination of portability and ease of use, and that will encourage subscribers to carry a femtocell when they travel. Another need exists in the art for a femtocell system that can be used with a laptop when a subscriber is in a hotel room, for instance.
A need exists for a femtocell that is designed with sufficient portability, ease of use, and low costs, so that many subscribers can purchase more than one femtocell, with one being for home use, another for the office, and a third for when they travel. There is a need in the art to allow multiple femtocells to be associated with an individual subscriber, and such that all femtocells can potentially support a single telephone bill, at potentially reduced rates from the mobile operator since calls traverse the Internet as opposed to the macrocellular network.
In addition, a further need exists in the art for femtocells that do not require a separate power supply, in order to reduce or eliminate use of an AC/DC wall adapter or batteries that require periodic replacement or recharging. Another need exists for femtocells to have the capability to support multiple mobile network standards such as GSM, UMTS, CDMA, CDMA2000/2001, plus future standards that have yet to be developed. There is a need in the art for a femtocell system that can support new standards even if they were not included when the subscriber signed up for the service. A need exists for a femtocell system that can support new standards by implementing a software defined radio that can be later updated on the femtocell system while supporting previously installed femtocell hardware.
There is a need for femtocell hardware to have sufficient capabilities to support the additional standards, such as the ability to operate in different frequency ranges with appropriate baseband processing, and to allow those hardware capabilities to be optionally added. Another need exists for femtocells that can securely authenticate subscribers, without requiring the mobile operator to deliver the security tokens, such as the combinations of RAND, SRES, and Kc in the GSM standard, since those security tokens may not always be available to the service provider. If the standard security tokens are available from the mobile operator, then there is a need for a femtocell system can implement them as well, in order to securely authenticate the MS and optionally cipher the channel according to the standard methods.
Further, a need also exists for femtocells that can also provide support for standard analog telephone or cordless telephone to be attached, in addition to a MS via radio. A need exists for a femtocell and service provider that can support the delivery of traditional “land line” voice services and telephone numbers through VoIP by connecting a traditional phone, similar to an analog telephone adapter (ATA). There is a need in the art for femtocell system that permits a telephone to ring even when the MS is away from the femtocell or turned off, and there is a need for a femtocell system to be able to support standard services such as voice mail, caller ID, call waiting, call forwarding, and others that can be delivered to the analog telephone through the femtocell.
And lastly, there are needs in the art for a femtocell system in which the process to configure and install the femtocell system so that it can obtain service in a quick and simple manner, since subscribers will most likely be performing the installations. A need exists in the art for a simple installation process of a femtocell system that is opposite to just shrinking a traditional BTS or picocell which usually requires a trained technician to install a BTS or picocell on the mobile operator's network, often spending several hours or more during that process.